I observe that: Balance of my each account remains unchanged if there is no transaction on the block. If there is a transaction, authorities' balances, slightly increase (I couldn't figure out with what percent each account gain a reward).

Also at each mined block,miner address returns: 0x0000000000000000000000000000000000000000

Do you mean Proof of Authority, not Proof of Stake? (That tutorial is for PoA.)
– Richard HorrocksJan 16 '18 at 17:26

Isn’t Proof of Stake and Proof of Authority same? Is there any difference between them? @Richard Horrocks
– alperJan 16 '18 at 17:45

2

Hi @Alper. There's a difference. PoA uses centralised, authority nodes to mint/approve new blocks being added to the chain. PoS, depending on how it's implemented, is more decentralised, and allows anyone to participate in the validation of blocks via a voting mechanism.
– Richard HorrocksJan 17 '18 at 18:38

Doesn't on POA authorized users, which allow to seal votes, will allow new users to be authorized also under clique()? @Richard Horrocks
– alperJan 18 '18 at 7:29